Centrifugal pump



April 23, 1935. O H, ER 1,998,754

CENTRIFUGAL PUMP Filed April 19, 1954 2 Sheets-Sheet 1 Q 1 3g N x g mfiflare/ INVENTOR ATTORNEY April 23, 1935. ofH, DORER 1,998,754

' CENTFIFUGAL PUMP Filed April 19, 1954 2 Sheets-Sheet 2 0300/ H Damp INVENTOR A TTORNE Y Patented Apr. 23, 1935 UNITED STATES PATENT OFFICE CENTRIFUGAL PUMP Application April 19, 1934, Serial No. 721,309

8 Claims.

This invention relates to centrifugal pumps and more particularly to centrifugal pumps for pumping hot oil or analogous fluids.

An object of the present invention is to provide a solid casing multi-stage centrifugal pump which embodies the advantages of a volute pump eliminating the disadvantages of split casing and diffusion ring pumps and in which the casing has a uniform bore throughout, and also a pump in which the impellers are arrangedto counteract end thrust and to maintain one stage pressures on the stufiing boxes, preferably the lowest stage pressures of the pump.

Another object of the present invention is to provide a multi-stage centrifugal pump as specified in which the stage pressures are utilized to maintain the stage forming diaphragms tight regardless of the arrangement of the impellers.

With these and other objects in view as may appear from the accompanying specification, the invention consists of various features of construction and combination of parts, which will be first described in connection with the accompanying drawings, showing a centrifugal pump of the preferred form, and the features forming the inven; tion will be specifically pointed out in the claims.

In the drawings:

Fig. 1 is a longitudinal section through a multistage centrifugal pump constructed in accordance with this invention.

Fig. 2 is a vertical section through the pump taken on the line 2-2 of Fig. 1 and showing one of the segments of the segmental ring in position immediately prior to its assembled position, such showing being by broken lines.

Fig. 3 is a plan view of a segment ring employed in the connection of the pump diaphragms.

Fig. 4 is an enlarged vertical section taken on the line 44 of Fig. 2 showing the method of connecting the stage-forming diaphragms.

In multi-stage centrifugal pumps particularly adapted for pumping hot oil, it is advantageous to avoid as many joints as possible in pump construction andalso to avoid the use of diffusion rings as well as to embody the advantages of a volute pump, such as, greater simplicity and a vaneless free volute spiral for diffusion action and collection of fluid as it leaves the impeller. Furthermore, it is desirous to maintain the diaphragms between the stages of the pump tight as well as to provide a uniform bore for the pump casing to permit the confining of the casing to reasonable size and simplicity. These various features are comparatively easy to obtain in a split casing pump. However, in the pumping of hot oil at high pressures it is difficult to maintain sufiiciently tight joints to prevent the leakage of the fluid pumped. a

The present invention provides a multi-stage centrifugal pump embodying a solid casing in 5 which all of the elements such as the impellers and diaphragms are inserted from the ends of the pump thereby providing a strong durable pump which is free from horizontal joints, is simple in construction and is particularly adaptable for the pumping of hot oil or other fluids.

Referring more particularly to the drawings, the improved centrifugal pump includes the easing I which, as illustrated in the drawings, is a. solid casing, open at both ends to permit the insertion of the impellers and diaphragm rings therein as well as to permit the passage of the impeller carrying shaft 2 therethrough. The impeller carrying shaft 2 has the impellers 3 mounted thereon. In Fig. 1 of the drawings a two-stage pump is illustrated, that is, a pump having two impellers 3 thereon. However, it is to be understood that any number of impellers and/or stages may be provided without departing from the spirit of the present invention.

The impellers 3 are arranged in back to back relation with the suction of the first stage impeller facing the packing 4 at one end of the pump while the suction of the second stage impeller faces the packing 5 at the opposite end of the pump. The fluid to be pumped is drawn in through the suction 6, passes through a first st v ejimpeller 3 into the volute I thereof from w iclr it passes through the conversion passages or channel 8 to the suction. of the second stage impeller. Fromthe second stage impeller the fluid passes into the volute 9 and from thence outwardly through the discharge III of the pump. The ends of the casingl are closed by suitable heads I I and I2 which carry the packings 4 and 5 and form closures for the casing. It will be noted by particular reference to Fig. 1 of the drawings that the joints between the ends I I and I2 in the casing I are all so arranged that none of these joints are subject to discharge pressure of 4 the pump.

. In a multi-stage pump of this type, and particularly where the impellers are arranged so that the packings and end joints of the casing will be subjected only to the lowest stage pressures in the pump, it is difficult to provide for the insertion of the impellers into the casing and also provide the proper diaphragm for separating the respective stages of the pump, that is, and maintain a constantbore of the pump casing. It is desirable to maintain a constant bore in the pump casing, first because of ease and relatively low cost of machining and second so as to permit the maintaining of the pump casing within reasonable size limits.

For the purpose of permitting the insertion of the impellers into the casing I and maintaining the individuality of the stages removable diaphragms 20 are provided. The diaphragms 20 comprise ring sections 2| and 22 which fit in the bore of the casing and are connected by clamping nuts or sleeves 22' which thread into the sections 2| and have suitable annular flanges 23 which fit in annular grooves 24 formed in the sections 22, as clearly shown in Fig. 3 of the drawings.

The diaphragm sections 2| and 22 have aligning annular grooves 25 and 26 formed in their outer peripheries which aligning grooves receive the segment rings 21. The segment rings 21 serve to connect and hold the sections 2| and 22 of the diaphragms in position within the casing and each of these segment rings are made up of four segments 28, 29, 38 and 3|.

In assembling the pump structure, the section 2| of the first diaphragm 20 is inserted through the end of the pump and placed in proper posi-,

tion and the segment ring 21 cooperating therewith is placed in the annular cut-out portion of groove 25. In assembling and positioning the segment ring 21 in place, segments 30 and 3| are properly positioned, being located and held in place by means of the pins 33. After the segments 3!] and 3| are properly positioned and lo- .cated, the segment 29 is forced into its proper position and finally the segment 28 is moved from the center outwardly into its position in the annular cut-out portion 25. The section 22 is then placed in position alongside of the section 2| and the clamping flanged nut 22' is tightened or threaded into the sections 2| for securely clamping the sections 2| and 22 together. Lugs 34 are formed upon the section 22 and extend into and beyond the cut-out portions 26 thereof, at spaced intervals as shown in Fig. 2 of the drawings. The lugs 34 have their outer surfaces tapered as shown at 35 so that as the section 22 is moved against the section 2| the wedge shaped lugs will force the segments 28 and possibly the segment 29 outwardly into their proper positions in the annular groove formed by the cut-out portions 25 and 26 and into the aligning cooperating annular groove formed in the casing thereby properly positioning the diaphragm forming sections and holding them in place. After the first diaphragm has been properly positioned and tightened in place, the first impeller is properly mounted upon the shaft, and the second diaphragm ring built up in the manner heretofore described. Finally after all of the impellers have been inserted in the pump and the diaphragm rings properly built up, the heads H or l2, depending on which end of the pump has been opened, is properly clamped in position and the pump is completely assembled and ready for operation.

By constructing the diaphragms in sections and assembling them as above described it is possible to provide a uniform bore throughout the length of the casing facilitating machining operations, and it is also possible to assemble thevarious impellers and diaphragms in a solid casing from either end of the casing thereby feli'minating the disadvantages of a split casing pump and permitting of the utilizing of the ad jvantage's of a volute pump in a solid casing.

By particular reference to Fig. 1 of the drawings it will be noted that the sections 2| and 22 of the diaphragms are subjected to stage pressures in such manner that the sections of the diaphragms will be urged towards each other during the operation of the pump. For instance, the rings or sections 2| and 22 of the first diaphragm, at the suction end of the pump are exposed respectively to suction or inlet pressure and one stage pressure discharge. The section or ring 2| of the diaphragm between the first and second stage of the pump is exposed to the discharge pressure of the first stage impeller while the section 22 is exposed to the discharge pressure of the next impeller, thereby providing a substantially overbalanced pressure on the diaphragms from the discharge end tending to urge the sections 22 against the sections 2| and also urging the segments of the segmental rings 21 in their proper positions through the medium of I the wedge shaped or beveled lugs 34.

It will be understood that the invention is not to be limited to the specific construction or arrangement of parts shown, but that these may be modified widely within the invention as defined by the claims.

What is claimed is:

1. In a multi-stage centrifugal pump, a solid casing open at its ends and free from horizontal splits, removable 'end closing heads for said casing, said casing having an impeller receiving bore therein of uniform diameter throughout the length of the casing, a plurality of impellers in said casing, and a plurality of removable diaphragms in said casing between said impellers, said diaphragms made up of a plurality of sections, segmental rings for connecting said sections to said casing, and clamping nuts for connecting said sections and their inner peripheries.

2. In a multi-stage centrifugal pump, a solid casing open at its ends and free from horizontal splits, removable end closing heads for said casing, said casing having an impeller receiving bore therein of uniform diameter throughout the length of the casing, a plurality of impellers in said casing, and a plurality of removable diaphragms in said casing between said impellers, said diaphragms made up of a plurality of sections, segmental rings for connecting said sections to said casing, clamping nuts for connecting said sections and their inner peripheries, and wedge shaped lugs on certain of said sections, for forcing the segments of said segmental rings into proper position.

3. In a multi-stage centrifugal pump, a solid casing open at its ends and free from horizontal splits, removable end closing heads for said casing, said casing having an impeller receiving bore therein of uniform diameter throughout the length of the casing, a plurality of impellers in said casing, and a plurality of removable diaphragms in said casing between said impellers, said diaphragms made up of a plurality of sections, segmental rings for connecting said sections to said casing, and clamping nuts for connecting said sections and theirinner peripheries, said diaphragms and impellers arranged whereby an unbalanced pressure will be exerted against the diaphragms to prevent leakage from a high pressure stage to a low pressure stage of the pump, said casing having vaneless' free volute spirals therein for diffusion action between the stages.

4. In a multi-stage centrifugal pump, a solid casing open at its ends and free from horizontal splits, removable end closing heads for 'said casing, said casing having an impeller receiving bore therein of uniform diameter throughout the length of the casing, a plurality of impellers in said casing, and a plurality of removable diaphragms in said casing between said impellers, said diaphragms made up of a plurality of sections, segmental rings for connecting said sections to said casing, and clamping nuts for connecting said sections and their inner peripheries, said casing having vaneless free volute spirals therein for diffusion action between the stages.

5. In a multi-stage centrifugal pump, a solid casing open at its ends and free from horizontal splits, removable end closing heads for said casing, said casing having an impeller receiving bore therein of uniform diameter throughout the length of the casing, a plurality of impellers in said casing, and a plurality of removable diaphragms in said casing between said impellers, said diaphragms made up of a plurality of sections, segmental rings for connecting said sections to said casing, and clamping nuts for connecting said sections and their inner peripheries, an impeller shaft, packing for said shaft atthe ends of said casing, said impellers arranged whereby said packing will be subjectedtothesuction and discharge pressures respectively of the lowest pressure stage of the pump.

6. In a multi-stage centrifugal pump, a solid casing open at its ends and free from horizontal splits, removable end closing heads for the easing, a plurality of impellers in said casing, a plurality of removable diaphragms in the casing between said impellers, said diaphragms made up of a plurality of sections, segmental rings for connecting said sections to said casing, and means for connecting said sections at their inner peripheries.

7. In a multi-stage centrifugal pump, a solid casing open at its ends and free from horizontal splits, removable end closing heads for said casing, said casing having an impeller receiving bore therein of uniform diameter throughout the length of the casing, impellers in said casing, a plurality of removable diaphragms in said casing between said impellers, said diaphragms made up of a plurality of sections, means connecting said sections to said casing at their outer peripheries, and means connecting said sections at their inner peripheries.

8. In a multi-stage centrifugal pump, a solid casing open at its ends and free from horizontal splits, removable end closing heads for said casing, said casing having an impeller receiving bore therein of uniform diameter throughout the length of the casing, impellers in said casing, a plurality of removable diaphragms in said casing between said impellers, said diaphragms made up of a plurality of sections, means connecting said sections to said casing at their outer peripheries, means on certain of said diaphragm sections for forcing said connecting means into position, and means connecting said sections at their inner peripheries.

OSCAR H. DORER. 

